U.S. patent number 4,613,452 [Application Number 06/664,397] was granted by the patent office on 1986-09-23 for aqueous acidic hydrogen peroxide composition containing enol ester activator.
This patent grant is currently assigned to Interox Chemicals Limited. Invention is credited to William R. Sanderson.
United States Patent |
4,613,452 |
Sanderson |
* September 23, 1986 |
Aqueous acidic hydrogen peroxide composition containing enol ester
activator
Abstract
The effectiveness of hydrogen peroxide for bleaching and
disinfecting at ambient to hand hot temperatures can be enhanced by
reaction with an enol ester a peracid generator (activator). The
present invention provides emulsions of enol ester activators in
aqueous acidic solutions of hydrogen peroxide containing a water
soluble emulsifier in at least 1 part per part by weight of
activator. The enol esters have either of the general formulae:
##STR1## Preferably, sufficient emulsifier mixture thereof is
present to enable the resultant emulsion to be clear demonstrating
the presence of thermodynamically stable micellar structures. In
preferred compositions, the activator is selected from vinyl or
isopropenyl or but-1-enyl or cyclohex-1-enyl acetate heptanoate,
octanoate or benzoate and divinyl adipate or phthalate, and
1,5-diacetoxypenta-1,4-diene. The compositions can be used as such
or upon dilution with aqueous media and in conjunction with
detergent compositions, and for cleaning and disinfecting absorbent
or non-absorbent materials.
Inventors: |
Sanderson; William R.
(Warrington, GB2) |
Assignee: |
Interox Chemicals Limited
(London, GB2)
|
[*] Notice: |
The portion of the term of this patent
subsequent to January 29, 2002 has been disclaimed. |
Family
ID: |
10550782 |
Appl.
No.: |
06/664,397 |
Filed: |
October 23, 1984 |
Foreign Application Priority Data
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Oct 26, 1983 [GB] |
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|
8328654 |
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Current U.S.
Class: |
252/186.23;
252/186.41 |
Current CPC
Class: |
C11D
3/391 (20130101); C11D 3/3947 (20130101) |
Current International
Class: |
C11D
3/39 (20060101); C09K 003/00 () |
Field of
Search: |
;252/186.23,186.41 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
92932 |
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Nov 1983 |
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EP |
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3003351 |
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Aug 1981 |
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DE |
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836988 |
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Jun 1960 |
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GB |
|
Primary Examiner: Terapane; John F.
Assistant Examiner: Thexton; Matthew A.
Attorney, Agent or Firm: Larson and Taylor
Claims
I claim:
1. A composition suitable for use in bleaching or disinfection
comprising an emulsion of an enol ester activator having either of
the following general formulae: ##STR3## in which each of R.sup.a
and R.sup.b represent hydrogen or a C.sub.1 to C.sub.5 alkyl
radical or a C.sub.2 to C.sub.4 alkenyl radical or a phenyl
radical, R.sup.a and R.sup.b being the same or different or
combining together to form a carbocyclic di-radical,
R.sup.c represents hydrogen or a C.sub.1 to C.sub.5 alkyl radical
or a phenyl radical or is combined with R.sup.a or R.sup.b and the
olefin group to form a carbocyclic radical,
R.sup.e represents hydrogen or a C.sub.1 to C.sub.8 alkyl radical
or a phenyl radical,
n is 1 or 2,
when n=1, R.sup.d represents hydrogen or a C.sub.1 to C.sub.8 alkyl
radical or a phenyl radical,
when n=2, R.sup.d represents a C.sub.2 to C.sub.10 alkylene
di-radical or a phenylene di-radical,
and m is an integer from 0 to 8, together with at least its own
weight of a water-soluble emulsifier in an aqueous acidic solution
of hydrogen peroxide.
2. A composition according to claim 1 in which hydrogen peroxide is
present in a mole ratio to the enol ester of at least 1:1.
3. A composition according to claim 2 in which the concentration of
hydrogen peroxide is from 1 to 8% w/w in the composition.
4. A composition according to claim 1 which contains sufficient
emulsifier for the emulsion to be visually clear.
5. A composition according to claim 1 in which the proportion of
activator is from 1 to 15% w/w and the proportion of emulsifier is
selected in the range of 5 to 30%.
6. A composition according to claim 1 in which the enol ester
activator of formula (i) or (ii) satisfies the condition that
R.sup.a is a hydrogen, methyl or ethyl radical and R.sup.b and
R.sup.c are each hydrogen or methyl radicals.
7. A composition according to claim 1 in which the enol ester
activator of formula (i) or (ii) respectively satisfies the
condition that R.sup.d is an ethyl, methyl, pentyl, hexyl,
2,4,4-trimethyl pentyl, 2-ethyl pentyl heptyl, phenyl, phenylene or
C.sub.2 -C.sub.4 polymethylene radical or R.sup.e is a methyl,
ethyl or phenyl radical.
8. A composition according to claim 1 in which the enol ester
activator of formula (ii) satisfies the condition that m is 0, 1 or
2.
9. A composition according to claim 1 in which the activator is
selected from vinyl or isopropenyl or butenyl acetate, heptanoate
or octanoate, divinyl glutarate or adipate or azelate or sebacate,
vinyl or isopropenyl benzoate, divinyl phthalate or iso- or
tere-phthalate, cyclohexenyl acetate, glutardienol diacetate or
sucindienol diacetate.
10. A composition according to claim 1 in which the emulsifier is
selected from water-soluble alcohol ethoxylates, alkyl phenol
ethoxylates, alcohol sulphates, linear alkyl benzene sulphonates
and/or alkyl esters of sulphosuccinates.
11. A composition according to claim 10 in which the activator is
selected from vinyl or isopropenyl or butenyl acetate, heptanoate
or octanoate, divinyl glutarate or adipate or azelate or sebacate,
vinyl or isopropenyl benzoate, divinyl phthalate or iso- or
tere-phthalate, cyclohexenyl acetate, glutardienol diacetate or
sucindienol diacetate, in a proportion of from 1 to 15% w/w, the
proportion of emulsifier is selected in the range of 5 to 30%, and
the concentration of hydrogen peroxide is from 1 to 8% w/w in the
composition.
12. A composition according to claim 11 which contains an aliphatic
alcohol having a C.sub.4 -C.sub.8 carbon chain in a weight ratio to
the emulsifier of up to 2:1.
13. A composition according to claim 1 which contains an aliphatic
alcohol having a C.sub.4 -C.sub.8 carbon chain in a weight ratio to
the emulsifier of up to 2:1.
14. A composition according to claim 13 in which the emulsifier is
anionic.
Description
The present invention relates to hydrogen peroxide compositions and
more particularly to aqueous hydrogen peroxide compositions
containing additionally a peracid generator, and to processes for
the manufacture of such compositions and their use in washing,
bleaching, or disinfection.
In earlier European Patent Application 83302056.3, publication No.
0092932, in the name of Interox Chemicals Limited, the difficulties
of providing a liquid system that can generate peroxy acids for use
in low temperature bleaching or in disinfection have been reviewed.
The specification also drew attention to earlier references to
members of the class of activators subsequently described therein,
namely enol esters having either of the general formulae: ##STR2##
in which each of R.sup.a and R.sup.b represent hydrogen or a
C.sub.1 to C.sub.5 alkyl radical or a C.sub.2 to C.sub.4 alkenyl
radical or a phenyl radical, R.sup.a and R.sup.b being the same or
different or combining together to form a carbocyclic
di-radical,
R.sup.c represents hydrogen or a C.sub.1 to C.sub.5 alkyl radical
or a phenyl radical or is combined with R.sup.a or R.sup.b and the
olefin group to form a carbocyclic radical,
R.sup.e represents hydrogen or a C.sub.1 to C.sub.3 alkyl radical
or a phenyl radical,
n is 1 or 2,
when n=1, R.sup.d represents hydrogen or a C.sub.1 to C.sub.3 alkyl
radical or a phenyl radical,
when n=2, R.sup.d represents a C.sub.2 to C.sub.10 alkylene
di-radical or a phenylene di-radical,
and m is an integer from 0 to 8.
In the invention described in said European Patent Application, the
enol esters are present dispersed in an aqueous acidic solution of
hydrogen peroxide. By so forming an emulsion, it was found that it
was possible to provide a composition containing the essentially
hydrophobic activator and aqueous hyrogen peroxide under such
conditions that it was storage stable relative to avox (available
oxygen) loss, but which still generated a peroxy acid when the
solution was rendered less acid or became mildly alkaline, such as
would be the case when it was employed in conjunction with a
conventionally available household detergent composition. The
specification further indicated that the term `emulsifier` in
respect of the activator meant that the emulsifier and activator
had HLB values the same as or not differing in practice
significantly from each other such that the activator is dispersed
in the composition. For the avoidance of doubt, it is recognised
that the matching of the HLB values for the emulsifier system and
the activator becomes more critical as the amount of emulsifier
system relative to the amount of activator is decreased. Thus, at
very low weight ratios of emulsifier system to activator,
satisfactory emulsion and in particular the formation of a
kinetically stable emulsion demands that the matching be relatively
tight. The corollary is, however, also recognised namely that where
the emulsifier system is present in an excess amount relative to
the activator the matching between the components can be relaxed,
in some instances substantially and still permit an emulsion to be
formed.
It will be recognised from a detailed study of the text of said
European Patent Application, that various preferred limits were
indicated for the concentration of the various components within
the composition. Thus, for example, the preferred range for the
aqueous phase, namely aqueous hydrogen peroxide, was from 40-95% by
weight of the composition, the balance being made up by the organic
phase which comprised mainly the activator and the emulsifier
therefor together with any other organic materials incorporated
within such a range, the organic phase is dispersed and the aqueous
phase continuous. It was further suggested that the emulsion
preferably contained from 3-35% of the activator and often at least
10% activator indicated that the minimum amount of emulsifier was
usually around 5-10% by weight thereof, based upon the activator,
naturally where the two components had matched HLB values. Somewhat
later in the specification, it was indicated that transparent
emulsions were generally unattainable unless the amount of
emulsifier present represented at least half the weight of the
activator and various examples were presented in which the weight
of emulsifier system represented 50 to 70 % of the activator. Thus,
it will be apparent to the reader that said EPA was concentrating
upon compositions in which the ratio of activator to emulsifier was
relatively low and therefore in which relatively tight matching of
the HLB values was appropriate.
It is the intention of the present disclosure to rectify any
inadvertent impression gained from the aforementioned EPA that
suitable emulsions of the activator and aqueous hydrogen peroxide
must always have very tightly matched HLB values for the
activator/emulsifier system.
Accordingly, it an object of the present disclosure to draw
attention to the fact that aqueous emulsions of such activators
which contain a similar or even markedly higher amount of
emulsifier than of activator may be suitable.
Accordingly, activator compositions described herein comprise
aqueous emulsions of one or more activators in classes i and ii
defined herein, together with at least its own weight of one or
more emulsifiers soluble in the aqueous phase, the proportion of
activator plus emulsifier in the composition comprising 5-60%, and
aqueous hydrogen peroxide comprises the balance.
Herein the activators are represented by the general formulae (i)
and (ii) employed in European Patent Specification 0092932, save
that the alkyl radicals R.sub.d and R.sub.e is from C.sub.1 to
C.sub.8.
Advantageously, the use of a higher ratio of emulsifier to
activator enables the resultant emulsions to tolerate more readily
variations in their ingredients and in the compositions containing
them and variations in storage conditions. In particular,
commercially available emulsifiers (surfactants) are subject to
variations in their composition, be it in their residual
impurity/manufacturing reagent content or in the distribution of
homologues. Examples include variations in the residual alkylate in
linear alkyl benzene sulphonate surfactant, variations in the
residual alcohol in alcohol sulphates and variations in the
distribution of homologues in ethoxylated products. Also, storage
and distribution of the emulsions are likely to be subject to
significant variations in temperature. The typical overall process
is more susceptible to success when implemented under normal
manufacturing conditions.
With the confines of the 5-60% range for the organics component, it
is preferable for the overall concentration of the two components
together to total at least 10% of the composition and in many
embodiments will be selected within the range of 15-50% of the
composition.
Theoretically at least, the concentration of activator in the
emulsion can be as low as desired, but in practice is rarely
selected below 1%. However, as its concentration is increased above
1%, it rapidly needs less total volume of emulsion to deliver a
desired dosage of peracid generator to a washing or disinfecting
solution. A proportion of activator of 1-15% w/w is suitable. The
emulsion formed can either be a macro-emulsion or can contain
micellar structures depending upon the nature of the emulsifier
chosen and its weight ratio to the activator. By choosing water
soluble emulsifiers, it is possible to form clear emulsions, i.e.
those containing micellar structures with higher concentrations of
activator than would be the case for solely water-insoluble
emulsifiers.
The emulsifiers that can be employed in the instant invention
compositions are generally selected from water-soluble nonionic and
anionic surfactants, or mixtures thereof. The class of anionic
surfactants includes in particular linear alkyl benzene sulphonates
and alcohol sulphates, alkyl sulphosuccinates, olefin
sulphates/sulphonates, sulphated derivatives of ethoxylated fatty
alcohols or alkyl phenols. Suitable classes of nonionic surfactants
include ethoxylated fatty alcohols, ethoxylated alkyl phenols,
condensates of fatty acids with ethylene oxide, fatty esters of
polyhydric alcohols and/or ethoxylated derivatives thereof, block
condensates of ethylene oxide and propylene oxide, ethylene oxide
derivatives of alkanolamines and fatty acid alkanolamides as well
as fatty amine oxides as examples of amphoteric surfactants.
Herein, the terms for the surfactants are used in their
conventional way, so that, for example, the hydrophobic moiety
normally comprises a hydrocarbon of carbon chain length 8-26
carbons, which may or may not be ethylenically unsaturated or
interrupted by an aromatic ring, and the degree of ethoxylation
when present typically from 6-50 moles of ethylene oxide per mole
of surfactant in many cases from 6-15 moles. All the classes of
surfactants that have been listed in the aforementioned European
Patent Specification pages 9 to 11, incorporated herein by
reference, can likewise be employed herein but naturally the
hydrophobic and hydrophilic moieties are selected together so as to
retain water solubility. A proportion of 5-30% emulsifier is
suitable.
The extent to which the matching of HLB values for the
activator/emulsifier can be relaxed in the context of the present
disclosure using high amounts of emulsifier can be gauged from the
fact that clear emulsions can be formed from water soluble anionic
emulsifiers such as alkyl benzene sulphonate, alcohol sulphates or
sulphosuccinates provided that the weight ratio of the emulsifier
to activator is generally at least 4:1 and in some instances from
2:1 to 4:1 also, in the range of activator concentrations from
1-10% w/w. At ratio of emulsifier to activator below those ranges
but at least 1:1, the emulsion is primarily a macroemulsion, but it
will be seen to comprise two phases only, i.e. does not separate
readily to a three phase system. Accordingly, one desirable range
of compositions contain at least 40 to 90% aqueous hydrogen
peroxide, at least 1% activator and at least 4 parts by weight
water-soluble anionic emulsifier per part of activator. In such a
range at ambient temperature the compositions are normally clear
and contain micellar structures and thereby enjoy excellent
physical stability.
A similar picture emerges in respect of the nonionic emulsifiers.
Thus taking divinyl adipate as a representative example, at least
of aliphatic activators, the ethoxylated and water-soluble nonionic
emulsifiers typically yield a clear emulsion at a weight ratio to
the activator of around 3:1/4:1 or higher. Taking vinyl benzoate,
it was possible even on occasions to employ a ratio as low as 3:2
for some such nonionic emulsifiers to activator. The effect of
closely matching HLB values is most apparent at the boundary change
between an apparent one phase to a visible two phase system, in
that for such systems the possible amount of activator that can be
included whilst retaining a clear composition is highest.
In addition, mixtures of the emulsifiers, such as a mixture of one
or more alkyl benzene sulphonates and/or alcohol sulphates and/or
sulphosuccinates with one or more water soluble alkyl phenol and/or
ethoxylated fatty alcohol or fatty acid, ethoxylated alkanolamide
or other ethoxylated nonionic emulsifier, can be used. The ratios
of the mixtures can be selected within wide limits, though, but
generally the anionic/nonionic ratio is in the range 10:1 to 1:10.
In the preferred region of e.g. 3:1 to 1:3 and by so doing, it is
often possible to extend the area within which the compositions are
clear rather than being strictly macroemulsions. In many instances
such co-operation between the two types of emulsifiers could enable
clear compositions to be formed containing 1 part activator per 2
to 3 parts by weight of the emulsifier system. An excellent example
comprises a 2:1 to 1:2 ratio of a nonyl phenolethoxylate with a
sulphosuccinate.
It is possible also to employ an intermediate weight aliphatic
alcohol having a C.sub.5 to C.sub.8 chain length to co-operate with
especially the anionic emulsifiers, in a weight ratio thereto often
of up to 2:1.
Where a mixed emulsifier system is used, it will be recognised that
some relaxation in the water solubility of one component of that
system can be permitted. Thus, for example, the aliphatic alcohols
referred to above, such as pentanol, would not be regarded as being
strictly water soluble.
In selecting the activator, the same criteria can be applied herein
as in the aforementioned European Patent Specification. Accordingly
in many embodiments R.sup.a, R.sup.b and R.sup.c in the formulae
for the activator, are each often selected as follows: R.sup.a from
hydrogen, methyl or ethyl radicals, and R.sup.b and R.sup.c from
hydrogen or methyl radicals or R.sup.a and R.sup.c combine with the
olefin moiety to form a C.sub.5 or C.sub.6 carbocyclic radical and
R.sup.b from hydrogen and methyl radicals. R.sup.a, R.sup.b and
R.sup.c can be selected independently from each other. Various
examples of moieties derived from the enols which are highly
favoured include vinyl, isopropenyl, isobutenyl, n-butenyl, and
cyclohexenyl moieties. R.sup.d and R.sup.e in the formulae are
often selected from methyl, ethyl pentyl, hexyl, 2,4,4-trimethyl
pentyl, 2-ethyl pentyl heptyl and phenyl, and R.sup.d additionally
from phenylene and C.sub.2 -C.sub.4 polymethylene radicals. In
formula (ii) m is often 0, 1, or 2. It will be further recognised
that it is convenient to select activators that are liquid in
themselves or with the emulsifier readily form liquid droplets or
readily suspended particles under the conditions of manufacture of
the emulsion. Accordingly, highly favoured activators from formula
(i) include vinyl acetate, isopropenyl acetate, butenyl acetate,
divinyl glutarate, divinyl adipate, divinyl azelate, divinyl
sebacate, vinyl benzoate, isopropenyl benzoate, divinyl phthalate
or isophthalate or terephthalate, divinyl hexahydrophthalate or
cyclohexenyl acetate. Other highly favoured activators include
vinyl hexanoate, vinyl heptanoate, vinyl octanoate,
vinyl-3,5,5-trimethyl hexanoate and vinyl-2-ethyl hexanoate and the
corresponding isopropenyl esters. From formula (ii) highly favoured
activators include glutardienol diacetate
(1,5-diacetoxypenta-1,4-diene) and succindienol diacetate
(1,4-diacetoxybuta-1,3-diene). Naturally, the propionate esters and
aforementioned C.sub.6 to C.sub.9 chain length carboxylate esters
corresponding to the aforementioned highly favoured acetate ester
activators can be employed alternatively. Furthermore, any two or
more of the activators can be employed in combination, if desired,
for example in order to assist the formation of a liquid activator
phase employing a higher molecular weight activator in conjunction
with a lower molecular weight activator, or to enable a higher
weight peracid such as perheptanoic or peroctanoic acid as well as
a lower weight peracid such as peracetic acid.
Other examples of R.sup.a or R.sup.b include vinyl and propenyl
radicals. In addition, it will also be recognised that where two
enol ester groups are present in the formulae, the corresponding
compounds in which only one of the enol groups or the carboxylic
acid groups as the case may be is esterified are also usable as an
activator. Thus, for example the monovinyl ester of adipic acid is
usable and likewise the monoacetate ester of glutaraldehyde.
Various of the enol esters are commercially available. It has been
found that those that are not can readily be made by one or more of
the methods of esterification, having selected the appropriate
enolisable carbonyl compound and the appropriate carboxylic acid
chloride, anhydride or ketene under conditions known to chemists to
promote enol ester formation for isopropenyl acetate and closely
related compounds, or the processes disclosed in GBPS827718, or in
the articles by Bedoukian in J. Am. Chem Soc 1964, V66, p1326 and
by Verekenova in Zh Obeshch Khim 1963, V33, p91.
The aqueous hydrogen peroxide normally comprises from 40 to 95% by
weight of the composition and correspondingly the organic phase,
mainly the activator and emulsifier comprises the balance of from
60 to 5% by weight. This corresponds to a weight ratio between the
organic and aqueous phase on mixing normally of from 1:20 to 2:3
and in many instances this ratio is selected in the range of 1:9 to
1:1. The concentration of hydrogen peroxide is normally at least
1%, desirably at least 3% and conveniently is not more than 20% and
quite often not more than 10%, all by weight of the composition. In
many of the instant compositions, hydrogen peroxide concentration
is in the range of 4 to 8% by weight of the composition. A
concentration of hydrogen peroxide of 1-8% w/w is suitable. The
balance of the aqueous phase comprises water which in practice is
often in the region of 30 to 85% of the composition weight. The
aqueous phase also contains sufficient water-soluble acid to
generate an acidic pH, preferably from pH2 to pH5. Such a pH may
often be obtained in the aqueous phase of the emulsion in practice
by dilution of commercially available hydrogen peroxide solutions
which contain a small amount of acidic stabilisers such as
pyrophosphoric acid and/or one or more phosphonic acids with
demineralised water, and often on emulsification a small proportion
of organic acid from the activator can transfer into the aqueous
phase. The pH of the composition can readily be monitored and if
necessary adjusted to the preferred range by suitable acid or base
introduction. The aqueous phase can additionally contain a small
amount of a thickener, such as about 0.5% by weight of the
composition of a xanthan gum, the precise amount being variable at
the discretion of the manufacturer to obtain a desired
viscosity.
In the present composition it is particularly preferable to employ
at least one mole of hydrogen peroxide per mole of enol ester
equivalent, i.e. the product of the molar concentration of the
activator and the number of enol groups per molecule. In practice a
substantial excess of hydrogen peroxide is often included to allow
for any loss thereof during storage and/or consumption during
subsequent washing or disinfection by substances other than the
activator. A further advantage of including hydrogen peroxide,
which increases as its proportion increases, is that a higher
concentration of the ester activator can be obtained whilst still
retaining a clear micellar solution.
The instant invention emulsions are primarily directed towards two
uses. In one use, the emulsion is used as a low temperature acting
bleach in the washing or laundering of household fabrics or in the
cleaning of non-absorbent articles in the home or in processes for
cleansing and/or sterilising apparatus or other hard surfaces, such
as tanks, pipes, bottles or other containers or for the bleaching
of cellulose, in the form of pulp, paper, yarn, thread or cloth,
under similar process conditions to those in which hydrogen
peroxide or the developed peroxyacid can itself be employed. By way
of example, the liquid bleach emulsion can be employed in a
domestic or commercial laundry process in conjunction with any
washing composition in order to enable that composition to be
employed at low wash temperatures and achieve good stain oxidation.
Such washing compositions can be used in their usual amounts, such
as from 0.5 to 10 g/l and comprise one or more anionic surfactants,
including soaps and synthetic detergents usually an alkyl aryl
sulphonate, an alkyl sulphate and/or an alcohol sulphate, and/or
one or more non-ionic surfactants including primary or secondary
alcohol ethoxylates, or a zwitterionic detergent or an ampholytic
detergent or a cationic detergent and the washing composition can
also include one or more detergent builders, and conventional
adjuncts such as soil anti-redeposition agents, buffers, optical
brighteners, suds control agents, etc.
When the emulsion of instant invention is employed in conjunction
with a solution of such an aforementioned washing composition, the
resultant aqueous washing solution generally has an alkaline pH,
frequently from pH8 to pH10, which promotes the per-hydrolysis of
the activator resulting in formation of a peracid or anionic
species. Alternatively, it is possible to employ the bleach in a
subsequent rinsing stage of a washing process in that there is
often sufficient alkaline solution retained by the articles being
washed to promote a mildly alkaline pH in at least the first rinse.
In either method of use, though, it is usual to employ a
concentration of hydrogen peroxide and activator which can generate
theoretically a concentration of available oxygen (avox) in the
washing/bleaching water in the peracid form of from 5-200 ppm and
often from 10-50 ppm peracid avox. For an emulsion containing 10%
hydrogen peroxide and about 18% vinyl acetate, a peracid avox in
the wash solution of 25 ppm can be obtained by addition of about
0.8 g emulsion per liter of washing solution. Corresponding amounts
can be calculated for other emulsions.
It will be recognised that by the use of high ratios of emulsifier
to activator, it is possible to obtain bleach activator
compositions which establish their own balance of nonionic to
anionic surfactants when used in conjunction with conventional
amounts of a base washing composition and therefore can minimise
the risk of impaired cleansing of surfactant-sensitive soils which
can occur if relatively low ratios of emulsifier to activator are
employed.
It will be recognised, furthermore, that an alternative approach is
facilitated by the use of the type of compositions described
herein. In this latter approach, the bleach activator composition
can be tailored for use in conjunction with a selected washing
composition so that the benefits of the bleach augment the
performance of that washing composition without inteferring
markedly with the cleansing of surfactant sensitive stains. This
can be achieved by matching the emulsifier system of the bleach
composition to the surfactant mixture in the washing composition
and then employing a high concentration of the emulsifier system
into which is introduced the selected activator in a relatively low
ratio thereto.
The second important use of the emulsions described herein is in
the disinfection of aqueous media and, as briefly referred to
earlier herein, the disinfection and/or sterilisation of surfaces
that come into contact with humans or animals or their food or
drink. In such an application, it is desirable to obtain a
concentration of disinfectant species matched to the time available
to carry out the disinfection. For processes in which the contact
time is expected to be long, concentrations of as low as 100 ppm
emulsion can be employed but where the contact time is likely to be
a matter of a few seconds or at the longest a few minutes, a much
higher concentration of emulsion is often preferable, for example
up to a concentration of 10 gpl. Generally, disinfection or
sterilising solutions can be made by simple dilution of the
emulsion by an aqueous medium but if desired, sufficient alkali to
generate a pH of 7-8.5 can be added. It has been found,
particularly in respect of enol esters derived from dialdehydes,
for example 1,5-diacetoxypenta-1,4-diene or
1,4-diacetoxybuta-1,3-diene, that pH of 7 or mildly alkaline to pH
8 tends to encourage the rate at which, and the extent to which the
combination of activator plus hydrogen peroxide (or generator
thereof) kills bacteria, such as spore-forming bacteria. At such
pH's there would appear to be an enhanced capability.
Having described the invention in general terms, specific examples
will hereinafter be described in great detail by way of
illustration only.
EXAMPLES
The following Examples 1-16 were obtained by first forming a
solution of the entire amount of the emulsifier in an aqueous
hydrogen peroxide solution (8.4% w/w) into which was then
introduced with vigorous mixing the selected amount of activator.
In the case of vinyl benzoate (VB) the activator was added at
ambient temperature whilst the divinyl adipate (DVAD) was warmed
beforehand to make sure it was liquid and pourable. The mixture was
then allowed to stand without stirring and its appearance was noted
after 30 minutes.
Examples 17 to 21 were performed similarly to Examples 1 to 16, but
with the interpolation of an extra step after a solution of the
first indicated emulsifier had been obtained. In that extra step
the desired amount of the second emulsifier/cosurfactant was
introduced, with the result that the concentration of hydrogen
peroxide was lowered proportionately below its initial value of
8.75% w/w, and the concentration of the first emulsifier was
likewise lowered.
The emulsifiers used were:
E.sub.a --linear alkyl benzene sulphonate (NANSA SS30)
E.sub.b --sodium lauryl sulphate
E.sub.c --nonyl/phenol ethoxylate (SYNPERONIC NP13)
E.sub.d --sodium dihexyl sulphosuccinate (AEROSOL MA80)
E.sub.f --alcohol ethoxylate (ETHYLAN CD916)
E.sub.g --nonyl phenol ethoxylate (SYNPERONIC NP10)
E.sub.h --alcohol ethoxylate (BRIJ 30)
E.sub.i --alcohol ethoxylate (ETHYLAN CD 919)
The various compositions are summarised in the Table below, all of
which were visually clear after 30 minutes. The %s of activator and
emulsifier are those of the final composition, not parts added to
100 parts of aqueous hydrogen peroxide.
THE TABLE ______________________________________ Example Activator
(% w/w) Emulsifier % w/w ______________________________________ 1
VB 5 E.sub.a 13 2 VB 7 E.sub.b 12 3 VB 14 E.sub.b 18 4 VB 4 E.sub.c
20 5 VB 10 E.sub.c 12 6 VB 15 E.sub.c 18 7 VB 8 E.sub.i 12 8 VB 13
E.sub.i 19 9 DVAD 4 E.sub.b 13 10 DVAD 9 E.sub.b 19 11 DVAD 5
E.sub.d 12 12 DVAD 5 E.sub.d 19 13 DVAD 4 E.sub.f 13 14 DVAD 7
E.sub.f 20 15 DVAD 4 E.sub.g 13 16 DVAD 7 E.sub.g 20 17 VB 8
E.sub.g /E.sub.d 13/9 18 VB 8 E.sub.i /E.sub.d 12/11 19 DVAD 8
E.sub.b /E.sub.h 10/23 20 DVAD 9 E.sub.g /E.sub.d 13/11 21 DVAD 6
E.sub.f /E.sub.d 16/12 ______________________________________
From the Table, it can be seen that many clear compositions can be
obtained even using anionic emulsifiers with the activators
described herein. Many of these Examples have been repeated but at
lower concentrations of emulsifier. In general it was found that
nearly proportionate amounts of activator could be accommodated
whilst still obtaining a clear emulsion, as can be seen also by
comparing Examples 5 and 6, or 7 and 8 etc. Various other
emulsifiers in the specified classes were tried and as a general
rule it was found that performance ran parallel with their class
representative specified in the Table. Thus, by way of example,
other alcohol ethoxylates with a different degree of ethoxylation
and/or derived from a different alcohol also produced an emulsion,
but usually the maximum ratio of activator to emulsifier for which
a clear composition resulted was not the same as that with E.sub.f.
Likewise other emusions can be produced by replacing the anionic
emulsifier with a fatty acid amide, such as coconut oil
ethanolamide. Likewise, similar emulsions are obtained when the
activator is vinyl heptanoate, vinyl octanoate, vinyl
1-3,55-trimethyl hexanoate or vinyl-2-ethyl hexanoate instead of
vinyl benzoate.
* * * * *